For example, the column housing used for an in-vehicle electric power steering apparatus is made of an aluminum die cast part. For example, such an aluminum die cast part is disclosed in the following Patent Document 1. According to Patent Document 1, reduction in manufacturing cost may be attained with a 5 mm or less thick aluminum die cast part with a HRB50 or greater Rockwell hardness, and even if casting defects arise, a quality aluminum die cast part with high strength may be provided. Moreover, for example, an aluminum die cast part strength evaluating method is disclosed in the following Patent Documents 2 and 3. According to Patent Document 2, for example, three-dimensional distribution data of cold flakes in a casting is obtained by applying a supersonic wave to the casting, detecting a blowhole or a cold flake in the casting based on supersonic-wave information of the casting, acquiring first three-dimensional internal defect distribution data, carrying out X-ray computed tomography on the same casting, detecting a blowhole in multiple cross-sectional images of the casting; acquiring second three-dimensional internal defect distribution data; and comparing the first three-dimensional internal defect distribution data to the second three-dimensional internal defect distribution data. Additionally, according to Patent Document 3, it is determined whether an aluminum die cast part has a defect by cutting down and extracting an inspection piece from a solidified molten metal in a runner near the gate of the aluminum die cast part; calculating an area ratio of the area of the cold flake exposed to the control surface of the extracted inspection piece to the entire area of the control surface, and comparing that ratio with a predetermined reference value.